I enjoy mnemonics - partly because my own memory is so bad for random things and so good for patterns (rhymes, for instance). Here are a few I know of - if you know others, write me and tell me about them!

Mnemonic Subject Explanation
Oh Be A Fine Girl, Kiss Me (Quick) Astronomy Stars by temperature - from a Class O blue-white giant, through a G-class yellow dwarf like Sol, to an M-class red dwarf (giant?). The Q-class are oddities like neutron stars and black holes, that don't exactly have a temperature.

Kindly Put Cat Out For Going Stinko or
Kings Play Chess On Five Green Squares
Biology Taxonomic groupings - Kingdom, Phylum, Class, Order, Family, Genus, Species
i.e. - Animalia, Chordata, Mammalia, Primates, Hominidae, Homo, Sapiens (guess who!)

HOMES Geography The five Great Lakes - Huron, Ontario, Michigan, Erie, Superior

Willie, Willie, Harry, Steve
Harry, Dick, John, Harry Three
1, 2, 3 Neds, Richard Two
Harry 4, 5, 6 - then who?
Edwards twain and Dick the Bad
Harry, Harry, Ned the lad
Mary, Bessy, James the vain
Charlie, Charlie, James again
William and Mary, Anna Gloria
Four Georges, William and Victoria
Edward, George, the same again
Elizabeth and that's the end
History Kings and Queens of England -
William the Conqueror, William Rufus, Henry I, Stephen, Henry II, Richard Lionheart, John, Henry III
Edward I, Edward II, Edward III, Richard II, (Wars of the Roses) Henry IV, Henry V, Henry VI
Edward IV, Edward V, Richard III, Henry VII, Henry VIII, Edward VI
(Lady Jane Grey left out), Mary, Elizabeth I, James I, Charles I, (English Civil War) Charles II, James II
William (III) and Mary (II), Anne, George I, George II, George III, George IV, William IV, Victoria
Edward VII, George V, Edward VIII, George VI, Elizabeth II and we're up to current times.